Lighting for the film industry started with sunlight about the beginning of the last century and thereafter evolved through the carbon arc to a mix of incandescent lamps, medium arc high intensity discharge lamps (e.g., HMI), and more recently, fluorescent lighting. To a greater or lesser extent, these light sources all required large amounts of electric power and generate large amounts of heat that is undesirable during film production. High power consumption is an especially difficult problem for location production where a supply of electric power may be limited unless portable electric generating plants are made available which can increase the cost of production.
In addition, the films that have been developed over the years have been standardized to a degree to have responses based on the spectral characteristics of specific light sources. In particular, two widely used films have based their responses on a incandescent 3200K tungsten source and a standard 5500 K daylight source as exemplified by KODAK Color Negative Film 5219 and KODAK Color Negative Film 5205, respectively. It is important therefore that any new light sources which might be developed for photography or cinematography have appropriate spectral power distributions for use with these films.